Using blender as a video converter for multiple files?
There is no direct conversion for this in Blender, but you can do this kind of thing using the Video sequencer/editor in the video editing tab of blender. First you open the video editing tab:
And then press SHFT+A to open a dropdown menu that will give you the option to add a movie. Press this, and Blender will take you to a browser. Select the movie (.avi) you want, and press 'select'. Now you have added a .avi (if you selected that) in your sequencer:
Now you can have the output of the video type set, and then sequence the video to a location of your choice:
Now you can render animation like you would any normal animation, and it will automatically sequence through the video editor, and output your video.